Just got back from two weeks in Thailand, and wanted to say thanks for all the tips I gathered here. The Spice Market at the Regent in Bangkok (recommended by a few folks here)was one of the best meals of my entire life, all for the whopping sum of $30 (way too much food - but as a solo diner, had to sample several things). The Chinese restaurant at the Peninsula, Mei Jiang, was a similarly lovely setting and the best Chinese meal of my life (I've never been to China or Hong Kong)- the "deep fried seafood and tofu dumpling" was somehow a soft cloud of tender chunks of seafood and pillowy tofu floating in a greaseless layer of crunch studding with black pepper. I may never eat a dumpling in NYC again.
I tried very hard to make it to the Soi Polo fried chicken place recommended by a poster here, but got turned back by a Bangkok downpour.
Once I left Bangkok, it was all about little noodle shops and street food, so it's hard to give specific recs. The Chiang Mai Cookery School, recommended by someone here, was an incredible amount of fun, and the dishes I created with their prodding (especially fish cakes - who would ever think that I would make fish cakes???) were delicious if I do say so myself.
Otherwise in Chiang Mai, I really enjoyed munching my way around the Night Market. Similarly, Chiang Rai's night market (a much manageable affair) was a delight. The "special banana pancake" (drizzled with coconut cream) sold by the pancake vender (20B=50 cents) at the street entrance to the Chiang Rai night market was, again, one of the best desserts I've ever had in a lifetime of searching out banana desserts.
I can't wait to go back, and appreciate all the help I got from people here.